| A | B |
|---|
| adaptive value | any trait that helps an organism survive and reproduce under a given set of environmental conditions |
| evolution | the process by which species have changed over time |
| extinction | the disappearance of all members of a species from Earth |
| fossil record | a collection of fossils that provides clues to the history of Earth's organisms |
| genetic variation | the normal differences found among offspring |
| geologic time | Earth's history as revealed by layers of rock |
| mutation | a change in the base sequence of DNA |
| natural selection | the process by which the organisms that are best adapted to a specific environment survive and produce more offspring than organisms that are not as well adapted |
| overproduction | the potential for a species to increase its numbers beyond the area's carrying capacity |
| theory | a concept that has been tested and confirmed in many ways and now is used by scientist to make predictions about the natural world |
| carrying capacity | the largest population of any single species that an area can support |
